R version of http://rogeralsing.com/2008/12/09/genetic-programming-mona-lisa-faq/
The code is quite similar to Alsing's C# version, except that the parameter values he used are unknown and may need quite a bit experimentation. This is not really GA in the classical sense.
The right mutation parameters may generate the nice incremental evolutionary path Alsing provided, but I have not personally reproduced them even though the picture does evolve towards the given picture.
I also provided a simple genetic algorithm version based on the rgenoud package.